The present invention relates to a process of recycling worn railroad rails.
There are known processes for recycling worn railroad rails which involve heating the rail within a furnace to a plastic state for molding thereof by means of rolling operations. Often, such rolling operations are associated with separate processing of cut portions of the rail, such as its head, web and base. In some instances, all portions of the worn rail are processed along one shaping line into bar products, such as fence posts or rebars.
The recycling of worn rails without cutting thereof has been proposed, as disclosed for example in U.S. Pat. Nos. 328,937, 852,983, 1,086,789 and 1,206,606. Such prior known methods of recycling worn rails have never proved successful in producing a one-piece billet or slab, because of problems created by the formation of laps, seams and folds during the rolling operations, giving rise to quality defects in the product produced. It is also known from U.S. Pat. No. 4,982,591 to heat a worn, one-piece rail to a plastic state which is initially deformed by a multi-stage rolling action to a slab constituted by flattened base and head extensions of an undeformed web portion of the rail. The slab is then edged in stages to effect thicknening of its intermediate portion and formation of a billet without any lapping, seaming or folding.
Further, it is known from U.S. Pat. Nos. 7,073,238 and 7,996,973 to heat the rail and slit it into two pieces in a first reduction pass and then subsequently pass the two pieces through a single mill pass line such that each piece of the rail is deformed to have a generally uniform shape. In the event that the rail has a through hole in a web portion of the rail, the slit preferably occurs through the area of the hole.
A problem encountered with the processing of rails, particularly where the rails are slit into separate pieces, is that the size and configuration of the head portion of the rails may vary greatly from rail to rail due to different wearing history of the bearing surface of the rail. Depending on when the rail was replaced, traffic conditions during rail usage, weather and orientation of the rail, the size and shape of the head portion may vary greatly from its initial size and shape. When the rail is slit into pieces before it is reshaped to any degree, the variations in the head size will be maintained as variations in the size of the pieces, making it difficult to process the rail pieces in a single line pass operation and to achieve substantially identical final end piece sizes.
A solution to this problem would be an improvement in the art.